Not saying this is the correct way to go, but it’s something you might want to consider, which is perhaps charging them per conversation the bot has. They might see this as a more results driven way to pay, as they’re only paying when it’s delivering value to their site and business, a bit like a PPC mode. 2 cents per user is 100/month (assuming 5000 users). Add in a trigger to increase the % of website visitors who use the bot and it could be beneficial for both. You could perhaps add something to the contract do they only pay for a user that reaches a certain stage of the workflow, so they aren’t paying if someone sends one message and then leaves, for example.